---
title: Using Git submodules
sidebar_title: Git submodules
description: Learn how to configure EAS Build to use git submodules.
hideTOC: true
---

import { Step } from '~/ui/components/Step';

When using the default Version Control Systems (VCS) workflow, the content of your working directory is uploaded to EAS Build as it is, including the content of Git submodules. However, if you are building on CI or have `cli.requireCommit` set to `true` in **eas.json** or have a submodule in a private repository, you will need to initialize it to avoid uploading empty directories.

## Submodules initialization

To initialize a submodule on EAS Build builder:

<Step label="1">

Create a [secret](/build-reference/variables/#using-secrets-in-environment-variables) with a base64 encoded private SSH key that has permission to access submodule repositories.

</Step>

<Step label="2">

Add an [`eas-build-pre-install` npm hook](/build-reference/npm-hooks/) to check out those submodules, for example:

```bash eas-build-pre-install.sh
#!/usr/bin/env bash

mkdir -p ~/.ssh

# Real origin URL is lost during the packaging process, so if your
# submodules are defined using relative urls in .gitmodules then
# you need to restore it with:
#
# git remote set-url origin git@github.com:example/repo.git

# restore private key from env variable and generate public key
umask 0177
echo "$SSH_KEY_BASE64" | base64 -d > ~/.ssh/id_rsa
umask 0022
ssh-keygen -y -f ~/.ssh/id_rsa > ~/.ssh/id_rsa.pub

# add your git provider to the list of known hosts
ssh-keyscan github.com >> ~/.ssh/known_hosts

git submodule update --init
```

</Step>
